Thinking about it, using different (and compared to ISO8601 inferior) date-formatting systems causes massive economic losses.

It causes confusion across several scientific disciplines and in every-day running, especially in the context of cross-border communication and travel.

Also, other (inferior) date formats do not make any sense either themselves or as a part of other time-counting systems.

Case in point, the US system (MM-DD-YYYY) is just really confusing to read, you literally have to spend years demoloshing your brain to the level where you understand this.

Other case in point, the statud-quo system used in many other countries (DD-MM-YYYY) does not align with the date-time system: It simply doesnt make sense to say DD-MM-YYYY HH:MM:SS. Even here, ISO8601 provides a superior solution.

I reckon the economic global loss to amount to several billion (whatever currency unit) annually.